1. Field of the Invention
The present invention relates to a printing system that is capable of integrating an ink-amount control unit for controlling the amount of ink supplied to a printing press with an ink-amount calculation unit for calculating an image area rate contained in pre-press data or pre-press reproduction data.
2. Discussion of the Background
It has been heretofore known an ink-amount control unit of the type that is electrically connected to a printing press and is designed to adjust the opening degree of an ink fountain key in the printing press, thereby supplying an amount of ink adapted for the pre-press data to a roller train of the printing press.
In order to calculate the amount of ink supplied, an ink-amount calculation unit, which is designed to calculate the image area rate contained in the pre-press data such as those for the four-color process printing and the spot color process printing, is employed. This ink-amount control unit controls the opening degree of the ink fountain key in such a manner as to supply ink to the roller train of the printing press by an amount adapted for the image area rate calculated by the ink-amount calculation unit.
Since there exist various types of the pre-press data such as those of PS (postscript) type, and PPF (Print Production Format) type, several ink-amount calculation units need to be set up to cope with these different types of data in some cases.
However, the above conventional arrangement may cause a trouble in controlling the amount of ink supplied, since the ink-amount control unit is electrically separated from the ink-amount calculation unit. Specifically, the above arrangement poses a problem of causing troublesome works such as those for transferring data representative of the image area rate calculated by the ink-amount calculation unit in a floppy disc, carrying the floppy disc to an installation site of the ink-amount control unit, and reading the data from the floppy disc.
Particularly, when the ink-amount control unit is to be set up at a place far from the ink-amount calculation unit due to a limited installation space, the operation of both units may further deteriorate the workability for performing various works as described above. In addition, when several ink-amount calculation units are set up at different places, the operator needs to walk among the ink-amount calculation units, which is time-consuming and deteriorates the maintenance performance. Also, there remains a possibility of damaging a floppy disc or any other external memory devices.
It is an object of the present invention to provide a printing system that provides ease of control enabling the operator to easily control the amount of ink to be supplied to the printing press based upon the image area rate contained in the pre-press data, and provides improved maintenance performance.
According to the present invention, there is provided a printing system that includes an ink-amount control unit for controlling the amount of ink to be supplied to a printing press based upon an image area rate contained in a pre-press data, and at least one ink-amount calculation unit for calculating the image area rate. The ink-amount control unit is connected to the at least one ink-amount calculation unit on a network.
The above arrangement with the ink-amount control unit and the at least one ink-amount calculation unit connected thereto on the network can omit the necessity of using an external memory device such as a floppy disc for distribution of the data between the units, so that the amount of ink to be supplied to the printing press can easily be controlled based upon the image area rate calculated by the at least one ink-amount calculation unit. In addition, the network connection provides ease of system administration and improved maintenance performance.
The above printing system preferably has an arrangement that the ink amount control unit creates a file therein, and the file rewritably stores the names of units connected on the network, which units including the ink-amount control unit and the at least one ink-amount calculation unit, and the names of folders created in the units connected on the network, each of the folders storing data representative of the image area rate. The ink-amount control unit refers to the file, and selects a corresponding data representative of the image area rate to be used for controlling the amount of ink to be supplied to the printing press.
According to the above arrangement, a proper image area rate data to be used for controlling the amount of ink can securely be selected by the reference to the file. In addition, storage of the names of the units, e.g., ink-amount calculation unit, ink-amount control unit or any other units, and the names of the folders created in the units can omit the possibility of unintentionally selecting an image area rate data which is not to be used. As another excellent advantage, an additional ink-amount calculation unit can easily be set up with connection to the other units on the network by editing the content of the file, or adding, changing, deleting or modifying a unit name in the file.
Preferably, the at least one ink-amount calculation unit comprises a computer having a keyboard as an information input means; and the file has a content rewritable via the at least one ink-amount calculation unit. With this arrangement, the content of the file can easily be rewritten by the keyboard of the at least one ink-amount calculation unit, unlike the conventional arrangement. Specifically, it is hard to edit the file via the ink-amount control unit, which is usually provided with a touch panel as an input means.
The ink-amount calculation unit is preferably provided with a display means for displaying information indicative of a corresponding position or order of the selected image area rate data with respect to an entire data group stored in the file. This display means improves an visual observation performance for the operator, since a corresponding position of the selected image area rate with respect to an entire data group in the file is properly displayed. As a result, a possibility of unintentionally selecting an incorrect data can be limited.